TLF4277 Demoboard Application Note Rev. 1.1, 2012-04-25 Automotive Power TLF4277 Demoboard Introduction 1 Introduction The TLF4277 Demoboard is a demonstration of the Infineon low drop out linear voltage regulator with integrated current monitor. The TLF4277 is the ideal companion IC to supply active antennas for car infotainment applications. The adjustable output voltage makes the TLF4277 capable of supplying the majority of standard active antennas. This application note contains the main information for the TLF4277 Demoboard. 1.1 General Description The TLF4277 is a monolithic integrated low drop out voltage regulator capable of supplying loads up to 200 mA. For an input voltage up to 40 V the TLF4277 provides an adjustable output voltage in a range from 5 V up to 12 V. The integrated current monitor function is a unique feature that provides diagnosis and system protection functionality. Fault conditions such as overtemperature and output overvoltage are monitored and indicated at the current sense output. The maximum output current limit of the device is adjustable to provide additional protection to the connected load. The IC can be disabled via the Enable function to lower the power consumption. The PG-SSOP14 EP package provides an enhanced thermal performance within a SO8 body size. 1.2 • • • • • • • TLF4277 Feature List • • • • • • Integrated Current Monitor Adjustable Current Limitation Adjustable Output Voltage Overvoltage Detection Output Current up to 200 mA Very Low Current Consumption Very Low Dropout Voltage 1.3 Wide Input Voltage Range up to 40 V Reverse Polarity Protection Short Circuit Protected Overtemperature Shutdown Green Product (RoHS and WEEE compliant) AEC Qualified Block Diagram RSHUNT VBAT RCS 1 CS1 I CS2 TLF4277 Internal Supply CI Bandgap Reference ADJ Current Monitor EN CQ Protection circuits BlockDiagram .vsd CSO Figure 1 Regulated Output Voltage Q Load E.g. Antenna Amplifier GND CSO R SO Block and simplified application diagram of TLF4277 Application Note 2 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Technical Specification 2 Technical Specification The chapter provides a brief technical description of TLF4277. 2.1 Adjustable Output Voltage The output voltage of the TLF4277 can be adjusted between 5 V and 12 V by an external output voltage divider, closing the control loop to the voltage adjust pin ADJ. The voltage at pin ADJ is compared to the internal reference of typical 1.22 V through an error amplifier. The error amplifier controls the output voltage. Q IQ R1 Saturation Control Current Limitation ADJ CQ Bandgap Reference GND BD_VoltageRegulator _Adjust.vsd Figure 2 R2 Application detail external components at output for variable voltage regulator The output voltage is calculated according to Equation (1): VQ = (R1 + R2)/R2 x VREF,int, neglecting IADJ (1) VREF,int is typically 1.22 V. To avoid errors caused by leakage current IADJ, we recommend to choose the resistor value for R2 < 27 kΩ. For example, for 8V output voltage the following resistors can be selected: R1 = 56.2 kΩ R2 = 10 kΩ VQ = (R1 + R2)/R2 x VREF,int = (56.2 + 10)/ 10 x 1.22 = 8.076 V The accuracy of the resistors for the external voltage divider can lead to a higher tolerance of the output voltage.To achieve a reasonable accuracy resistors with a tolerance of 1% or lower are recommended for the feedback divider. Application Note 3 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Technical Specification 2.2 Current and Protection Monitor Functions The TLF4277 Demoboard provides a set of advanced monitor functionality. The current flowing into the power stage can be monitored at the CSO output. In addition the current limitation can be adjusted via external resistors. Events of the implemented protection functions are reported through dedicated voltage levels at the CSO output. This information can be processed by an external µC for system analysis and failure identification. The monitored events are over-current, overvoltage, and temperature shutdown. RSHUNT V BAT R CS1 ICS 1 I CS2 C S1 C S2 to pow er s tage C urrent M onitor M onitor C irc uits OC -D etec tion OV- D etec tion Buffer T SD -D etec tion Current _ Monitor .vsd GN D C SO I CSO C CSO Figure 3 R CSO Block diagram current and protection monitor To reduce possible effects from the supply voltage VBAT additional filtering of the supply voltage is recommended. A combination of a 100 nF capacitor and an additional buffer capacitor of 10 µF or higher should be placed as close as possible to the IC terminal, which are connected to VBAT. Figure 4 shows the output level at the CSO pin versus the operation or fault condition. The graph is valid for the following set up of external components: RSHUNT = 1Ω RCS1 = 100 Ω CCSO = 2.2 µF RCSO = 1.5 kΩ Application Note 4 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Technical Specification VCSO [V] 3,2 Short Circuit to V BAT 3.1 V typical 3,0 2,95 Thermal Shut Down 2.80 V typical 2,65 Current limitation and SC to GND 2.55 V typical 2,45 Linear Current Sense Band up to 2.45 V 0 163 170 Figure 4 Output levels and functionality of the CSO output1) 2.2.1 Linear Current Monitor ICS2 [mA] Inside the linear current monitor area the current driven out of the CSO pin is proportional to the voltage which is measured between pin CS1 and CS2. The level of the current ICSO can be adjusted according to Equation (2): R SHUNT V BAT – V CS2 I CSO = -------------------------------= I CS2 × -------------------R CS1 R CS1 Adjustment ICSO (2) R CSO ( V BAT – V CS2 ) × R CSO V CSO = -------------------------------------------------------- = V SHUNT × ------------R CS1 R CS1 Adjustment of the voltage level for VCSO (3) 1) The graph is just an example and only valid for an certain configuration of the external components Application Note 5 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Technical Specification 2.2.2 Adjustable Output Current Limitation The TLF4277 has an adjustable current limitation for the current flowing into the power stage (pin CS2). If the level of the voltage drop across the sense resistor RSHUNT is higher than the desired linear monitor range the output current of the TLF4277 will be limited. 2.55V × R CS1 I CS2,lim = -------------------------------------R SHUNT × R CSO Setting of the adjustable current limitation (4) A voltage level of 2.55 V typical, as shown in Figure 4, will be applied at the CSO pin. To achieve a current limitation of 170mA the following configuration can be used: × 100Ω- = 170mA I CS2,lim = 2.55V ---------------------------------1Ω × 1.5kΩ RSHUNT = 1Ω RCS1 = 100Ω RCSO = 1.5kΩ 2.2.3 Overvoltage Detection To detect a possible short circuit of the output to a higher supply rail the TLF4277 has an overvoltage detection implemented. An overvoltage will be detected, if the voltage level at the ADJ pin is 20% higher than the internal reference voltage VREF,int, which is typically 1.22 V. Under this condition the CSO pin will be driven through an internal voltage buffer with the voltage level of 3.10 V typical as shown in Figure 4. 2.2.4 Thermal Shutdown Detection If the junction temperature exceeds the overtemperature shutdown threshold defined in , the TLF4277 will disable the output voltage. In such a case the voltage level of 2.80 V typical will be applied at the CSO pin, as shown in Figure 4. 2.3 Enable Function The TLF4277 can be turned on or turned off via the EN Input. When voltage levels higher than VEN,high are applied to the EN Input the device will be completely turned on. A voltage level lower than VEN,low sets the device to low quiescent current mode. In this condition the device is turned off and is not functional. The Enable Input has a build-in hysteresis to avoid toggling between ON/OFF states, if signals with slow slope are applied to the input. Application Note 6 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3 Demoboard The TLF4277 Demoboard is equipped with TLF4277 and the necessary external components. Figure 5 TLF4277 Demoboard V1.1 3.1 Operating Conditions To avoid damage of the Demoboard, the maximum of the operating range defined in Table 1 must be followed. Table 1 Input / output operating range 1) Parameter Symbol Limit Values Min. Max. Unit Board Supply VIN 9 40 2) V Regulator Output VOUT 5 12 2) V Current Monitor Out CSO 0 5 V Enable Input LOW ENlow 0 0.8 V Enable Input HIGH ENhigh 2.0 40 V 1) The demo board is operating at ambient temperature of 25°C. 2) The max. value depends on the max. rating of external components on the board. Application Note 7 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3.2 1. 2. 3. 4. 5. Quick Start Procedure Set the jumpers on the board to select the desired test setup (refer to Chapter 3.3). With power off, connect the input power supply to VIN and GND. Connect the load between VOUT and GND. Preset the load current at 10 mA. Turn on the input power supply. Make sure that the input voltage does not exceed 40 V. Slowly increase or decrease the load current while monitoring the voltage at VOUT and CSO. 3.3 Board Configuration The TLF4277 Demoboard can be easily configured with the jumpers on the board. The board provides the following configuration options: • • • Output voltage: 5 V or 8 V. Current limitation: 54 mA or 170 mA. Enable function. 3.3.1 Output Voltage Setting The TLF4277 Demoboard provides two output voltage options 5 V and 8 V, which can be configured by setting the jumpers JP2 and JP3 (see Figure 9). Table 2 Jumper setting for output voltage JP2 JP3 Output Voltage close open 5.075 V1) open close 8.076 V1) 1) Nominal value. 3.3.2 Current Limitation Setting The TLF4277 Demoboard provides two output voltage options 54 mA and 170 mA, which can be configured by setting the jumpers JP4 and JP5 (see Figure 9). Table 3 Jumper setting for current limitation JP4 JP5 Current Limitation close open 54.25 mA1) open close 170.00 mA1) 1) Nominal value. 3.3.3 Enable Function The jumper JP1 on the TLF4277 Demoboard can be used to deactivate the Enable function by connecting the EN pin to the input pin, then the linear regulator is always on while it is supplied. When J1 is open, the Enable signal can be supplied from the EN test point on the board. Table 4 Jumper setting for enable function JP1 Enable Function close EN is connected to input, the Enable function is deactivated. open EN can be supplied externally, the Enable function can be used. Application Note 8 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3.4 Typical Performance In this chapter, the typical performance of the current and protection monitor functions are shown with lab measurement results. All measurements are done on TLF4277 Demoboard under the following condition: • • Tambient = 25°C Vin = 13.5 V 3.4.1 Current Monitor Performance Setup 1: 8 V output voltage (JP2 open, JP3 close) 170 mA current limitation (JP4 open, JP5 close) The typical current monitor performance is shown in Figure 6. The current sense accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet . 3 3 2,5 2,5 V_CSO (V) 1,5 1,5 Accuracy (%) 2 2 V_CSO Accuracy 1 1 0,5 0,5 0 0 0 50 100 150 200 I_CS2 (mA) Figure 6 Current monitor performance with setup 1 Application Note 9 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard Setup 2: 5 V output voltage (JP2 close, JP3 open) 54 mA current limitation (JP4 close, JP5 open) The typical current monitor performance is shown in Figure 7. The current sense accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet . 3 3 2,5 2,5 2 1,5 1,5 1 Accuracy (%) V_CSO (V) 2 V_CSO Accuracy 1 0,5 0,5 0 0 0 10 20 30 40 50 60 I_CS2 (mA) Figure 7 Current monitor performance with setup 2 3.4.2 Current Limitation Performance Setup 1: 8 V output voltage (JP2 open, JP3 close) 170 mA current limitation (JP4 open, JP5 close) The typical current limitation performance is shown in Table 5 in comparison with the nominal value. The current limitation accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet . Table 5 Current limitation value with setup 1 Nominal value Measured typical value 170.00 mA 171.65 mA Setup 2: 5 V output voltage (JP2 open, JP3 close) 54 mA current limitation (JP4 open, JP5 close) The typical current limitation value is shown in Table 6 in comparison with the nominal value. The current limitation accuracy is specified in section 7.2 on page 17 of the TLF4277 data sheet . Table 6 Current limitation value with setup 2 Nominal value Measured typical value 54.25 mA 55.32 mA Application Note 10 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3.4.3 Thermal Shutdown While the output voltage is switched off due to overtemperature, the voltage measured at CSO pin is shown in Table 7 in comparison with the typical value in the TLF4277 data sheet . Table 7 CSO output voltage during thermal shutdown Value in data sheet (Typ.) Measured typical value 2.8 V 2.809 V 3.4.4 Overvoltage Detection When VOUT is short connected to VIN, an overvoltage will be detected. Under this condition the voltage measured at CSO pin is shown in Table 8 in comparison with the typical value in the TLF4277 data sheet . Table 8 CSO output voltage during overvoltage Value in data sheet (Typ.) Measured typical value 3.1 V 3.115 V 3.5 Schematic Figure 8 TLF4277 Demoboard V1.1 schematic Application Note 11 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3.6 Bill of Material Table 9 Bill of material Part Value Package B1 Banana jack BABU4MM B3 Banana jack BABU4MM B4 Banana jack BABU4MM B5 Banana jack BABU4MM B6 Banana jack BABU4MM C1 10u/50V C2220K C2 100u/50V CPOL-EUE C3 10u/16V not mounted C1206 C4 2u2/10V C0805 C5 10u/16V C0805 C6 100n C0805 EN LSP10 LSP10 IC1 TLF4277 SSOP-14 JP1 Jumper JP1E JP2 Jumper JP1E JP3 Jumper JP1E JP4 Jumper JP1E JP5 Jumper JP1E R1 1R/1%/1W R2010 R2 100R R0805 R3 31.6k/0.1% R0805 R4 56.2k/0.1% R0805 R5 10k/1% R0805 R6 4k7/1% R0805 R7 1k5/1% R0805 Application Note 12 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard 3.7 Board Layout Figure 9 TLF4277 Demoboard V1.1 top layer component placement Figure 10 TLF4277 Demoboard V1.1 top layer Application Note 13 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Demoboard Figure 11 TLF4277 Demoboard V1.1 bottom layer Application Note 14 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Restrictions 4 Restrictions This Demoboard is offering limited features allowing you only to evaluate and test the Infineon products. The Demoboard is not an end product (or finished appliance), nor is it intended or authorized by Infineon to be integrated into end products. You are not authorized to use the Demoboard in any production system. Application Note 15 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Reference 5  Reference TLF4277 Data Sheet Application Note 16 Rev. 1.1, 2012-04-25 TLF4277 Demoboard Revision History 6 Revision History TLF4277 Demoboard Revision History: Rev. 1.1, 2012-04-25 Previous Version(s): Rev. 1.0, 2012-03-12 Page Subjects (major changes since last revision) 15 Restrictions disclaimer added. Application Note 17 Rev. 1.1, 2012-04-25 Edition 2012-04-25 Published by Infineon Technologies AG 81726 Munich, Germany © 2012 Infineon Technologies AG All Rights Reserved. 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